The purpose of this research program is to investigate the causes of hereditary neurological diseases, with the goal of developing effective treatments for these disorders. A genetic outreach program allows the identification and characterization of patients and families with hereditary neurological diseases. Specific research accomplishments in the past year include the following: (1) collaboration in the identification of the genetic defect responsible for spinocerebellar ataxia type 20; (2) a collaborative genetic outreach program in Bamako, Mali; (3) collaboration in the identification and evaluation of candidate genes for Larsson-Linderholm syndrome, familial autoimmune myasthenia gravis, Charcot-Marie-Tooth disease type 2C, and a new form of hereditary spastic paraplegia.